California Smog Check Requirements: The Complete Guide
California requires a Smog Check for most gasoline, hybrid, and alternative-fuel vehicles from model year 1976 onward, and diesel vehicles from model year 1998 onward. Whether you actually need to get tested right now depends on why you're dealing with the DMV — renewing your registration, transferring ownership, or registering a car in California for the first time all have different rules.
When do I need a smog check for registration renewal?
Most vehicles need a Smog Check every two years as part of registration renewal. Your DMV renewal notice will tell you directly whether a test is due — it also says whether you must go to a STAR certified station. Vehicles eight model years old or newer are exempt from the renewal test and instead pay an annual smog abatement fee (see our exemptions guide for the exact fee amounts).
Do I need a smog check to buy or sell a used car?
Change-of-ownership sales generally require a valid Smog Check certificate. For a private-party sale, the certificate has to be dated within 90 days of the sale; for a dealer sale, the dealer's certificate can be up to two years old. Vehicles four model years old or newer are exempt from this requirement and pay an $8 smog transfer fee instead, and transfers between immediate family members (spouse, domestic partner, parent, child, sibling, grandparent, grandchild) are exempt entirely.
Do I need a smog check to register an out-of-state vehicle in California?
Bringing a vehicle into California from another state generally requires a Smog Check as part of first-time registration here, subject to the same model-year exemptions that apply to renewals.
Worked examples by vehicle age
| Situation | What applies |
|---|---|
| Registration renewal, vehicle is 6 years old | Within the 8-year renewal exemption — pays the $20 annual abatement fee instead of testing. |
| Registration renewal, vehicle is 11 years old | Past the 8-year exemption window — a biennial Smog Check is required. |
| Private-party sale, vehicle is 2 years old | Within the 4-year transfer exemption — buyer/seller pays the $8 transfer fee, no test needed. |
| Private-party sale, vehicle is 7 years old | Past the 4-year transfer exemption — seller needs a valid certificate dated within 90 days of sale. |
| Sale between parent and child, any vehicle age | Exempt entirely as an immediate-family transfer — no test, no transfer fee. |
How do I find out exactly what my vehicle needs?
The single most reliable answer is your DMV renewal notice — it states your specific requirement, including whether a STAR station is mandatory for your vehicle. If you don't have a notice in hand, the rules above cover the large majority of cases. Once you know a test is required, search by city or zip code to find a licensed station near you, with STAR certification and repair capability shown for each one.
Glossary
- STAR
- California's higher-standard certification tier for smog check stations, reserved for stations that meet stricter equipment, training, and performance requirements set by BAR.
- BAR
- The Bureau of Automotive Repair, the California state agency that licenses smog check stations and sets Smog Check program rules.